O-[2-(Boc-aMino)ethyl]-O′-(2-MaleiMidoethyl)ethylene glycol

Mal-PEG2-NH-Boc is a PEG linker containing a maleimide group and a Boc protected amine group. The hydrophilic PEG spacer increases solubility in aqueous media. The protected amine can be deprotected under acidic conditions. The maleimide group will react with a thiol group to form a covalent bond, enabling the connection of biomolecule with a thiol.